Candidate integrity is assessed during the UPSC interview process through behavioral evaluations and situational questions. Interviewers gauge a candidate's honesty, transparency, and ethical principles. Candidates may be asked about their past decisions and how they handle dilemmas to understand their moral compass. Responses are scrutinized for consistency and clarity, reflecting a candidate's character. Additionally, interviewers observe non-verbal cues such as body language to gauge confidence and sincerity, which are crucial for a civil servant's role.